In many electrical and electronic products, control software and/or control data is provided in an electrically programmable non-volatile memory, of which a FLASH memory (also called FLASH ROM) is typical. For example, the product may be a set-top box. During development or modification of the product, the FLASH memory often needs to be programmed or reprogrammed. During manufacture, the FLASH memory may need to be programmed once the FLASH memory is in the product. When the product is used in the field, the FLASH memory may also need to be reprogrammed with updated contents.
Sockets can be provided on a circuit board to enable the FLASH memory to be removed for programming or reprogramming. However, such sockets represent additional cost and size, and may also be a source of potential unreliability. A memory chip is also vulnerable to damage when being inserted in, and removed from a socket. A modern FLASH memory device is generally a surface mount device that is very fragile and can easily be damaged by insertion into and removal from a socket. Soldering the FLASH memory to a circuit board provides cost savings, a smaller size, and greater reliability. However, in order to facilitate reprogramming of a soldered-in FLASH memory, a small memory programming application program can be stored in a protected portion of the FLASH memory that cannot be erased. The resident application program can then be executed to program the rest of the FLASH memory. A main disadvantage is that the resident programming application permanently occupies a portion of the available memory, and thereby limits the amount of free memory available for the intended product software. Another disadvantage is a lack of flexibility because the software to be programmed into the FLASH memory has to be made in a way that is compatible with the resident programming application. Difficulties commonly arise updating the resident programming application itself, because the programming application has to be executed to load software into the FLASH memory. A further disadvantage is the work to pre-program the FLASH memory with the resident programming application before the FLASH memory can be installed on the circuit board.